dansean1

iTrader: (2)

Based on my mods ( and DR's) can anyone guestimate what ill run after installing the 9 inch?
How much slower will I go (hp loss, weight)?

I think Im better off a lil slower but a strong rear end than risking a 7.5 inch.

Im speculating on times for La invasion.

RoDan

you might lose a touch MPH, but your ET might not suffer much at all. A buddy of mine went from stock 10bolt to a dana 60 and he didn't lose any mph. Same gear ratio and everything, I mean everything else was the same.

dansean1

iTrader: (2)

yea, I have some buddies who are saying I'll lose about 30-40hp turning the rear end and then the weight factor plays a part too.

I know it take some power to turn but coming out on sticky tires, 4.10's at 5000rpm, I can't imagine going that much slower...

Jimmard

iTrader: (12)

I went from 13.5 @ 105 to a 12.69@ 109. Only changes were stronger driveshaft, new torque arm, and a 9" 4.11s trutrac. It was at a different track...

dansean1

iTrader: (2)

Ok, well you guys are giving me hope.

But how are you able to run with a hp loss?

I also have and will put in the spohn adjustable torque arm with trans relocation crossmember.

My friends were really saying im going to lose .5 in the quarter or more!

I figured a .1 or so but they are saying thats with the motor stock hp (bolts ons), the rear will just slow the car down.

Maybe they're hating.

Jimmard

iTrader: (12)

You're not going to run slower, you will run quicker.... Unless you had 4.11s before in your 10 bolt as well?

dansean1

iTrader: (2)

you guys w/ the 9 inch, on a sticky tire (and good driveshaft/suspension) what are you dropping the clutch at?

Jimmard

iTrader: (12)

I'm on a 275/40R17 nitto and I heat them up really good, rev it up to 4500 and slip a little off the line, its good for consistant 1.8 60s with a best of 1.75. If I had a better tire I could launch harder and cut better 60s.

edit: heres the video of it http://s81.photobucket.com/albums/j2...t=M2U00030.flv

dansean1

iTrader: (2)

I have a 3.42 rear stock now. The 9 inch will be installed in the next 4 weeks.
I ran a 14.3 at LACR track in palmdale, ca before it closed. It was my first time with my car with a bad slave and I thought it was the clutch so I took it easy too!

I'll have 315's DR's out back. thats another thing. my buddies really believe that I blow off the tires at anything higher than 4500rpm. I disagree. Im gonna install my line lock for a good burn out.

So you suggest 4500's and letting the clutch slip slightly or just dropping the hammer?

I personally think, as you all do, that with the 9 inch and 4.10s on DRs and a good burnout and decent launch, the car will be a mover.

BTW, nice video and good pass.

You guys are on stock motors except for basic bolt ons right?

Jimmard

iTrader: (12)

I have a lid and cutout and thats it for power mods, I wouldnt even call it a bolt on car lol. If I drop the clutch on the launch the nittos break loose and spin like crazy so I just slip the clutch til the car gets moving a little bit, then I drop the hammer.

dansean1

iTrader: (2)

thanks for the input guys.
maybe ill bet money with my buddies on this since Im going to go faster.

Anyway do a before and after dyno?

How is daily driving now on city and freeway? rpm/mph/6th gear? gas mileage? Im curious.

Jimmard

iTrader: (12)

Dont count your chickens before they hatch, you'll jinx yourself lol. Car feels exactly the same city/freeway. Rpm is obviously a little higher cruising, you can check everything here www.f-body.org/gears Gas mileage went down a little I'm sure, but nothing ive paid attention to. The ride got a little more harsh on hard bumps, I just think that the koni SAs arent up to the job of the extra weight back there. They are leaking so I am going to upgrade to DA's for the rear to try to fix that. Other than that, with the trutrac, it feels like the stock rear, altho it definitely is louder with the whine/howl at around 60, and f*ckin pinion seal, passenger side axle seal, and the drain plug all leaked, and no the breather tube is not pinched.

wrencher

iTrader: (2)

If your gonna drop in a 9" might as well get some slicks IMO as well.
Then do some 5K + dumps & see what it'll do!

ls2pontiac

iTrader: (1)

do 5k clutch dumps wont you break the input shaft or something else in the transmission as well? i am waiting for my 9 inch to finally get the hell in my car, but im still not gonna dump the clutch on it unless i have to do a burnout at a meet or something.

that reminds me. will i be able to dump from 2nd gear at 3000 rpm and get on the brake with 4.11 pro streets or is it just gonna slip the clutch?

LSGunZ28

iTrader: (8)

Ok well since you were running a 3.42 before and now you have 4.10s Youll run faster than before and wont lose MPH.... and since you have a stronger rear you can run stickier tires and/or launch higher and take off, and cut faster 60's


However its bull how these guys are saying it wont make you slower, generally, if you ran the same gear ratio as before, the bigger ring gear and heavier diff will make you handle more laousy, due to unsprung weight and eat up some HP... But since you can launch better, you will go faster at the track, yes... and a numerically higher gear ratio... Even better... But dont fool yourself, you will dyno less, but the route you are going at the track you will see improvements for sureeee!

dansean1

iTrader: (2)

I've called up some shops, they say mph will reduce but et should remain same maybe drop some. They say outta the hole will be faster but its robbing hp and there's weight so its not going to acceralate overall all that much quicker.
I think Ill go quicker but not much. Such mixed reviews. La invasion will be the true test.

If I leave on a 315, hooking and shifting good, I can't imagine not seeing a 13.5.

My friends are like 14.5, probably slower..."30 hp to be robbed is a lot" according to them but there are pro's in other areas to.

Ima check out the mph/rpm link.

neeshSS

14.5??? slap them in the face. And quit freaking out, it will be ok.

dansean1

iTrader: (2)

haha, yea and when they say 14.5 they are saying it seriously!!! I hate this but Im gonna drop a 15.0.. My buddies even said 15's are possible!!!
Great friends huh?!? Usually they advocate for you, not against you.

red_ryderSS

iTrader: (1)

Ditch the nittos, get some et streets, put the car on somewhat of a diet to make up for the added nine inch weight and launch that sumbitch. Atleast that's what I'm doing after I install my 9 inch If ur worried about the tranny, rebuild it stronger

neeshSS

man they are out of their minds, unless you were running thousands and thousands of feet above sea level you wouldn't run in the 15's, A bolt on ls1 with 4.10s and sticky tires will surprise the hell out of them.